Some beginner questions

[Larrin]

In the tempering article you can see that tempering is more sensitive to temperature than time. So fluctuations in temperature may result in the effective tempering temperature being the peak of the fluctuations.

 

[Drake Donovan]

Thanks for the replies guys. If i don't know something i ask......so i ask a lot

Thx Drake, now back to your thread mate. By the way, i like the design on the right hand side, but without the finger choil and if it was full flat grind. I'd save my pennies and buy that.. Without the choil so i can hold different ways, and the flat grind because they slice so freely. in my laymans opinion.

Well, it did become a full flat grind, haha. Thanks for the encouragement and opinions!

If your anything like me, you’ll keep burning, and burning, and burning your poor fingers...
Maybe someday I will find relief when all feeling is lost... or maybe I’m doing it wrong


Can’t wait to see some progress!

Ah yeah, my fingers are getting a bit roughened up for sure! Here are some shots from today-- I think they are pretty ready for HT. Boy oh boy, did I learn a lot of lessons from making these things... The paper design and calculations are definitely great things to reference initially-- but not at all deterministic of the outcome! I think that the edges are a bit thin, so I think I'll sand them back some to avoid potential warping. Any other advice for my next steps is appreciated!

In the tempering article you can see that tempering is more sensitive to temperature than time. So fluctuations in temperature may result in the effective tempering temperature being the peak of the fluctuations.

That's a good point. So perhaps fluctuations are only potentially useful if you can set the maximum temperature of the cycle. Or perhaps they are not useful at all!

 

[Ruukuu]

Just aesthetic. I would round the shoulders at the back of the tangs more. Also a little bit on the angle point on the spine of the blade, so it matches the sweep of the cutting edge a little more ( on the top knife )

But that's just my personal thoughts. If you like to look then that's all that matters in the end

 

[Drake Donovan]

Just aesthetic. I would round the shoulders at the back of the tangs more. Also a little bit on the angle point on the spine of the blade, so it matches the sweep of the cutting edge a little more ( on the top knife )

But that's just my personal thoughts. If you like to look then that's all that matters in the end

I appreciate your thoughts, and you inspired me to be a bit more creative with the ass end on my next blade (see below)!

Something I realized with these first blades is that the bevel will only be as good as the jig-- so I remade the jig with a better understanding of how it would work and more attention to detail.



As you can see- I had to test it out with a couple of different knives. A root chopper for the kitchen and a dagger-ish blade to test out double-edge making. It works much, much better than the first jig I was using!

The reason I had extra time to make jigs and a couple of new blades? Well, heat treating isn't going so well....


I was initially excited because the test piece seemed to get hard after I heated to non-magnetic and then quenched in canola. The file skated right along the surface. So, I threw it on the concrete pretty damn hard to see if I could get it to break since I have read some makers suggest that it will be as brittle as glass at this stage, but I couldn't get the thing to break (perhaps because it is still 1/8" thick, or perhaps because it is only partially hardened). Oh well.

I figured I would go ahead and see what I could do with a real blade. I tried the little blade and after quenching the file will skid along about 90% of the edge, but it will still bite into the tip and the heel a bit. This is despite my best efforts to heat evenly-- I think the 2 or so inches of blade that I can put in the fire at once is just insufficient to heat the entire edge simultaneously for quenching, no matter how much I move it.

My plan now is to head to the hardware store and see if I can get some firebricks and make some sort of little chamber on top of my burner that offers a larger space with more uniform heat. I figured I would have the firebrick "oven" be open on only the front, since the blades are small and the flame is coming from directly below.

 

[Ruukuu]

Love the fact you carry on even with setbacks. I would probably have given up by now ( i'm pretty useless at times )
Can't wait to see a finished knife
I have no doubt the setbacks will become less and less as you figure things out and it will all become second nature to you.

 

[Drake Donovan]

Love the fact you carry on even with setbacks. I would probably have given up by now ( i'm pretty useless at times )
Can't wait to see a finished knife
I have no doubt the setbacks will become less and less as you figure things out and it will all become second nature to you.

I'm having way too much fun to give up, haha. I can't wait to get a finished knife either! It will be a learning process to get the scales all shaped-- that I am sure of.

I agree about setbacks. Even from knife to knife I feel like I am progressing so much-- the first blade took at least 3x longer than the more recent blades and I don't have to go back and correct things that I did wrong. For instance-- on the first knife I went straight from the Magicut filing to 220grit sandpaper. I burnt through a whole lot of sandpaper. Now I draw file with a mill smooth before I start sanding and it saves and unimaginable amount of time!

Update on the heat treat-- IT WORKED (I think). None of the hardware stores in town had any fire bricks, so I improvised... I messed with the air intake and chopped up an old paint can to act as a sort of forge. After nearly dying due to burning paint fumes and letting the shop air out, I was able to harden both edges fully. I am still pretty limited in size of blade I can heat evenly, so I'm nervous about trying the two larger knives with this set up. But I do feel that these two blades have fully hardened and tempered edges!




Question-- it seems that I can "see" where the blade has hardened, and I think you'll notice what I mean in the pictures... I'm wondering if this is just correlation with where the steel was most in the flame, or if this visual is somewhat representative of "true" hardening? I definitely got it non-magnetic, but color perception and decalescense are not as easy to interpret for my novice eyes.

Time to sand, cheers!

 

[N.W. Gean]

I've noticed in my own experiences that when the scale "pops off" the way it did on the edges, that means the steel in that area hardened. I believe JT mentioned this a while back in one of his threads about heat treating bad steel.

 

[Willie71]

Do a search for refractory supplies in your area. I found a local supplier who stocks nearly everything I needed.

 

[Drake Donovan]

I've noticed in my own experiences that when the scale "pops off" the way it did on the edges, that means the steel in that area hardened. I believe JT mentioned this a while back in one of his threads about heat treating bad steel.

Awesome, thanks for your knowledge!

Do a search for refractory supplies in your area. I found a local supplier who stocks nearly everything I needed.

I actually was able to get to a local scrapyard and they had pallets of the 9x5 firebricks for $2 a piece! Score! At that price, I almost want to go back and stock up so I can build a proper HT oven in the future.

That's where the good news ends though. Take a real good look at that clip point blade and tell me if y'all see anything funky! Talk about setbacks... what a bummer! Oh well, I have some time to spend in the shop today to try again.

 

[Drake Donovan]

I gathered myself after the death of my first blade and considered finishing it... then I decided it would be more fun to see what its guts looked like! Snapped clean in half. Into the trash!



Anyhow, I made a decent forge with those fire bricks and the outdoor burner. I could keep an 1/8th inch 6 inch blade evenly heated in it! I also got to finish up the other, stouter blade I was working on-- so here are some final pictures.




I made a lot of mistakes so it's not perfect, but each blemish is a lesson. Any suggestions you all have would be greatly appreciated. Onto the next blades!

 

[weo]

then I decided it would be more fun to see what its guts looked like

And a lot more informative too.
I'll defer to those with more experience and knowledge than me, but it looks like you overheated the edge quite a bit. If you notice the difference in grain size between what I think is the edge 1/2 (orange ovals) and the spine. The spine is nice and creamy, which is what you want the whole blade to look like, and the grain is a lot larger on the other half. This is also possibly part of the reason why the crack only went 1/2 way?

Excessive heat causes grain growth. I'll suggest doing a search (using the custom search engine in the stickies) on grain size for more info. Recently someone posted a thread with a pic of what differences in grain size looks like.

I see you're in Eugene, Drake. I'll suggest checking out the 5160 club. http://www.elementalforge.com/5160Club/

 

[Drake Donovan]

And a lot more informative too.
I'll defer to those with more experience and knowledge than me, but it looks like you overheated the edge quite a bit. If you notice the difference in grain size between what I think is the edge 1/2 (orange ovals) and the spine. The spine is nice and creamy, which is what you want the whole blade to look like, and the grain is a lot larger on the other half. This is also possibly part of the reason why the crack only went 1/2 way?
View attachment 1361219
Excessive heat causes grain growth. I'll suggest doing a search (using the custom search engine in the stickies) on grain size for more info. Recently someone posted a thread with a pic of what differences in grain size looks like.

I see you're in Eugene, Drake. I'll suggest checking out the 5160 club. http://www.elementalforge.com/5160Club/

Thanks for your insight on the HT, I do appreciate it. Overheating the edge would make sense since I did try to harden it twice.. Perhaps the crack formed on/after the first attempt, and then the heat was able to penetrate up the crack very easily on the second attempt causing it to dramatically overheat. I could try to snap the blade at another section and see if it looks similar (although snapping a 3 inch by 1 inch piece of 1/8th inch steel seems daunting).

That club seems really neat. Lots of great resources and I hope they'll start meeting in person again sometime soon. Cheers for that knowledge!!